Tontti

#include <iostream>
#include <vector>
#include <algorithm>


using std::cin;
using std::cout;
using std::cerr;
using std::endl;
using std::vector;

int main () {
  int n, m, num, val;
  int min, cur;
  int result(0);
  char c;
  cin >> n >> m >> num;

  min = (int) ceil(sqrt(num));

  vector<vector<int> > table(n+1, vector<int>(m+1, 0));

  for (int i = 1; i <=  n; ++i) {
    for (int j = 1; j <=  m; ++j) {
      cin >> c;
      if (c == '*') {
        val = 1;
      } else {
        val = 0;
      }
      table[i][j] = val + table[i][j-1]  + table[i-1][j] - table[i-1][j-1];
    }
  }

  cerr << table[n][m] << " min=" << min  << endl;

  for (int i = 0; i <=  n-min; ++i) {
    for (int j = 0; j <=  m-min; ++j) {
      int begin = min;
      int end = std::min(n-i, m-j);
      // cerr  << endl << i << "-" << j << endl;
      while (begin <= end) {
        cur = (end + begin)/2;
        val = table[i][j] - table[i+cur][j]  -  table[i][j+cur] + table[i+cur][j+cur];
        // cerr << cur << ": " << val << endl;
        if (val == num) {
          ++ result;
        }
        if (val > num) {
          end = cur - 1;
        } else {
          begin = cur + 1;
        }
      }
    }
  }

  cout << result << endl;
  return 0;
}

Test 1

Group: 1

Verdict: WRONG ANSWER

10 min=1

Test 2

Group: 1

Verdict: ACCEPTED

100 min=3

Test 3

Group: 1

Verdict: ACCEPTED

43 min=4

Test 4

Group: 1

Verdict: ACCEPTED

41 min=3

Test 5

Group: 1

Verdict: ACCEPTED

55 min=2

Test 6

Group: 2

Verdict: WRONG ANSWER

8 min=1

Test 7

Group: 2

Verdict: WRONG ANSWER

86 min=3

Test 8

Group: 2

Verdict: ACCEPTED

124906 min=159

Test 9

Group: 2

Verdict: ACCEPTED

125105 min=112

Test 10

Group: 2

Verdict: ACCEPTED

124737 min=71

Test 11

Group: 3

Verdict: WRONG ANSWER

9 min=1

Test 12

Group: 3

Verdict: WRONG ANSWER

89 min=3

Test 13

Group: 3

Verdict: ACCEPTED

1998008 min=633

Test 14

Group: 3

Verdict: ACCEPTED

1999726 min=448

Test 15

Group: 3

Verdict: ACCEPTED

1999981 min=283